1.To provide a service facility that will utilize investigator-derived DNA constructs to create founder transgenic and gene knockout mice that can be used to address questions relevant to obesity and nutrition research. 2. To provide consultation to obesity and nutrition researchers regarding general aspects of transgenic and gene knockout work, the use of tissue-specific promoters, the generation of transgenic and gene knockout constructs, and the establishment and monitoring of genetically modified mouse colonies. 3. To provide training in methods required for the generation of transgenic and gene knockout DNA constructs.